J. Hortl. Sci. Vol. 6(1):52-55, 2011

Short communication

Diversity of pollinators and flora in cashew

D. Sundararaju* Directorate of Cashew Research Puttur (D.K.), Karnataka-574 202, India E-mail: [email protected]

ABSTRACT Seven species of bee that maintained constancy on cashew flowers were identified from coastal Karnataka [(Pseudapis oxybeloides (Smith), Lasioglossum sp. and Halictus sp., Halictidae; Braunsapis sp., smaragdula (F.) and Ceratina sp., )] and four species from coastal Tamil Nadu [(Ceratina (Pithitis) binghami Cockerell, C. smaragdula, Braunsapis sp. and P. oxybeloides)]. Time spent by for visiting the flowers ranged from 0.8 to 25.1 seconds per flower. Diversity of flora recorded during 2003-08 as floral resources for nectar for all the above bee species during lean and flowering periods of cashew - both at coastal Karnataka and Tamil Nadu - is presented in this paper. Key words: Diversity of bees, floral resources, cashew

Fruit-set in cashew is mainly influenced by the activity fixed spots in cashew during the flowering season of 2005- of pollinators (Reddi, 1993; Thimmaraju and Lakshmi Raju, 06 was recorded. For this, one square meter of the canopy 1993; Freitas and Paxton, 1996). In the East Coast of Tamil was marked in early-season (NRCC Selection-2), mid- Nadu, 32 species of visited cashew inflorescences season (Bhaskara) and late-season (Chintamani- 1) (Ambethgar, 2002). In the West Coast of India, flowering varieties. In each variety, visits of bee pollinators Devasahayam (1986) and Sundararaju (2000, 2003) reported at fixed hour (11.00 hr and 14.00 hr) were observed for a various species of bee such as Pseudapis oxybeloides period of 10 minutes continuously for 30 days from initiation (Smith), Ceratina smaragdula (F.), Apis spp., of flowering in panicles. Highest population recorded either Lasioglossum sp., Trigona iridipennis Smith and one at 11.00hr or 14.00hr was accounted as population for that unidentified halictid visiting cashew. Based on the number day. Role of bee pollinators in fruit-set was observed by of free pollen-grains on their bodies, honey bee (A. caging single trees completely with nylon net (size 40 mesh) mellifera) and the solitary bee (Centris tarsata) were found similar to that in studies of Freitas and Paxton (1996). Total to be efficient pollinators of cashew (Frietas, 1997; time spent per flower by some of the bees was recorded Bhattacharya, 2004). Studies were therefore undertaken to with the help of a stop-watch and video-graph. Simultaneous document the diversity of bee pollinators occurring on observations were made within cashew plantations on cashew in the cashew belt of coastal Karnataka and in diversity of flora that served as floral resources during lean coastal Tamil Nadu. Simultaneously, information on other periods, and additional floral resources during flowering flower resources (flora) occurring in cashew plantations periods of cashew. during the lean season and flowering period of cashew was Species of bees which visited cashew flowers, and collected, in order to suggest methods for conservation and bees carrying pollen grains on their legs and body hairs, management of pollinators. were collected and identified. There were seven species Diversity of bee pollinators was assessed by collecting from coastal Karnataka Pseudapis oxybeloides, bees that maintained constancy on cashew flowers in the Lasioglossum sp. and Halictus sp. (Halictidae); Braunsapis cashew belt of coastal Karnataka and in coastal Tamil Nadu, sp., Ceratina smaragdula and Ceratina sp. (Apidae), and by undertaking surveys during 2004 – 2006. Bee species four species from coastal Tamil Nadu: Ceratina (Pithitis) were identified using taxonomic keys developed by Batra binghami Cockerell, C. smaragdula, Braunsapis sp. and (1977). Visitation of bee pollinators at fixed hours and on P. oxybeloides. These species were observed as mainly

*Present address: National Bureau of Agriculturally Important Insects, Hebbal, Bangalore-560 024 Diversity of bee pollinators and flora in cashew collecting pollen grains, followed by feeding on nectar and During 2006-07, a single tree of ‘Bhaskara’ variety were categorized either as pollen-bees native-bees, wild was caged all over with mosquito net, in the centre of a bees or non-Apis bees (Batra, 1994). Even though plantation at Puttur and geitonogamous pollination (through honeybees (Apis florea F., A. cerana indica and A. dorsata gravitational fall of pollen grains) was completely prevented F., Apidae) visited cashew flowers in both the regions, these by removing the upper panicles. Every day, the tree was were mainly involved in feeding on nectar and, very rarely, observed between 11.00 and 12.00h. Most of the time, at in collecting pollen. Stingless bee (Trigona iridipennis least twice or thrice, bee species P. oxybeloides dashed Smith, Apidae) alone collected both nectar and pollen grains. against the mesh of the cage from outside the of cage and However, pollen billets on their corbiculae were loaded in ultimately, could not enter the cage because of its larger the form of a brownish, slimy mass. Though the occurrence body-size, and the close mesh of mosquito net. This type of of above species of Apis, P. oxybeloides, C. smaragdula external attraction may be due to volatiles emanating post- and Lasioglossum sp. have already been reported by anthesis in cashew flowers. As a result, no fruit-set was Devasahayam (1986), Reddi (1995), Sundararaju (2000), observed even upto 45 days from onset of flowering in the Ambethgar (2002) and Bhattacharya (2004), four species particle. And at the same time, normal fruit-set showing viz., Halictus sp., Ceratina sp., Braunsapis sp. and Ceratina various stages of fruit development was observed on all the (Pithitis) binghami in this study have been recorded for surrounding un-caged trees. Subsequently, in the caged tree, the first time from cashew plantations of coastal Karnataka belated fruit-set was spotted after 45-60 days from of and Tamil Nadu. As per reports of Ambethgar (2002), Apis flowering. By this time, all the surrounding un-caged trees mellifera L. was sighted in coastal Tamil Nadu, but could not be sighted in the repeat survey undertaken during 2004- Table 1. Visitation by bees on different varieties of cashew trees 2006. Similarly, Bhattacharya (2004) reported occurrence Bee species Visit of bee within 10 minutes (no./panicle/day) during 30 observational days of Bombus spp. in West Bengal, but it is surprising to note NRCC Bhaskara(M) Chintamani(L) that Bombus spp. specific to the cooler high-altitude region Selection-2 (E) (1350m to 8400m above MSL (Abrol, 1997) was seen on Stingless bee 0.280(30) 0.003(3) 0.036(8) cashew. Recently, the extent of pollination in cashew with (Trigona iridipennis ) a maximum of upto 46.8%) after the visit of A. cerana Apis cerana indica 0.027(14) 0.026(10) 0.014(11) indica, was documented by Sundararaju (2011). (honey bee) A. florea 0.025(17) 0.007(3) 0.000 Total time spent on the flower by bees was accounted Non-Apis spp. 0.021(9) 0.136(26) 0.036(16) Total 0.353(30) 0.162 (26) 0.086(27) for by keeping time with a stop-watch and recording with a Figures in parentheses are no. of days sighted out of 30 observational video camera (Tables 2 and 3) and was seen to range from days; E, M, L: Early-, mid- & late-season flowering 0.8 to 25.1 seconds flower. Whenever pollen alone was variety, respectively collected, the time spent was found to be minimum (0.8 to Table 2. Time spent by different species of bees* per cashew flower 5.0 sec flower-1). Combined collection of pollen and nectar, or collection of nectar alone, time spent was maximum (5.0 Name Mean± S.D (seconds)** Range (seconds) Apis cerana indica 2.31 ± 1.35 0.8 - 9.0 to 25.1 sec. / flower). This is in contrast to an earlier study Apis florea 8.25 ± 2.61 1.2- 22.2 by Sundararaju (2000) who observed P. oxybeloides as Ceratina 13.62 ± 1.30 5.0- 25.1 spending 2.0 seconds on pollen collection alone. The (Pithitis) binghami abundance of bees on early-(NRCC Selection-2), mid- Braunsapis sp. 9.43 ± 1.36 2.0- 22.0 *Recorded with a stop-watch; * * Mean of minimum 10 observations (Bhaskara) and late-season (Chinthamani - 1) flowering varieties was 0.35, 0.16 and 0.09 bees panicle-1, respectively, Table 3. Visitation of bees on cashew flowers as recorded on video in a constant period of 10 minutes, during 2005-06 (Table 1) camera at Puttur (coastal Karnataka). Under undisturbed video Bee species No. of bee visits Time recording, in a canopy area containing 15 panicles during a on 15 panicles within a spent / flower period of 20 minutes, visit of 2-3 A. cerana indica and 1-5 period of 20 minutes (seconds) P. oxybeloides bees was found to be low in cashew. This Day1 Day2 Day3 Mean± S.D. Range is in concurrence with earlier reports of Ohler (1979) and Apis cerana indica 3 2 2 3.6±1.0 2-5 Free (1993). Pseudapis oxybeloides 1 5 4 4.1±3.9 1-18

53 J. Hortl. Sci. Vol. 6(1):52-55, 2011 Sundararaju had panicles at an advanced stage of fruiting and were on Even though P. oxybeloides, Lasioglossum sp. and in the verge of cessation of flowering. Since the caged tree Braunsapis sp. visited cashew and B. lacera, B. oxydonta had no panicles bearing fruits, flowering was to be observed and R. parviflora, the respective bees maintained with continuous, without any cessation. Therefore, the caged tree specific parallel-exclusive constancy pattern on cashew was critically observed. Finally, through visual observation, alone. But, at Vridhachalam (coastal Tamil Nadu), during entry of Lasioglossum sp. through the mesh of the cage the flowering period of cashew, exclusive constancy by was confirmed especially at the site where flower panicles Ceratina (Pithitis) binghami, Braunsapis sp. and P. touched the mesh of the cage. Also visit to new flowers of oxybeloides was also observed on Cleome viscosa and L. the caged tree, by bee species already present inside the aspera, common weeds in cashew plantations. Similar level cage, was seen. Since the caged tree maintained active of exclusive parallel-constancy by these species of bees flowering while all the surrounding trees were on the verge was not seen on other varieties of cashew except of cessation of flowering, bees must have been attracted to ‘Bhaskara’. Thus, the high-yielding variety Bhaskara, was flower panicles touching the mesh of the cage. Subsequently, found to be a bee-pollinator attractant variety in coastal Tamil through the mesh of the cage, these bees may have made a Nadu. This can be further popularised all over coastal Tamil forced entry. As a result, a final fruit-set in 71.2% of panicles Nadu. Existence of the above floral resources during both with a mean of 1.2 nuts/panicle was recorded. Whereas, in lean and flowering periods of cashew in coastal Karnataka the surrounding un-caged trees that showed activity of bees and Tamil Nadu, can help conserve/manage these bees of the above-mentioned species (since onset of flowering), whenever any recommended insecticides (used for final fruit-set was observed in 81.3% of panicles, with a management of cashew pests) caused a depression in bee mean of 2.1 nuts/panicle. This level of fruit-set on the caged population. All the same, use of existing recommended tree was possible mainly due to involvement of smaller bees insecticides has not affected pollination in cashew in the past (Sundararaju, 2000, 2003 and 2004). This is because that entered through the mesh of the cage. This is in non-Apis bees do not have any scope for contact with contradiction with earlier studies by Freitas and Paxton insecticide-treated cashew flowers, except on the day of (1996) who reported meager fruit-set in a completely caged insecticide application. Growth of B. lacera and O. tree (since larger bees were excluded and smaller bees were adscendens at the respective regions was noticed only in not involved in pollination of cashew). limited locations and, therefore, needs to be spread to other Diversity of flora recorded during 2003-08 as floral locations for conservation. It is also interesting to note that resources for all the above bee species in lean periods at most of above-mentioned flora are native weeds in cashew coastal Karnataka included of Lindernia antipoda L. L. plantations, excepting Mimosa pudica. These native weeds crustacean L. and L. ciliata (Colsm.) (Scrophulariaceae), are fairly non-invasive and are capable of growing under Spermacoce hispida L. and S. ocymoides Burm. partial shade of the cashew canopy. However, Muntingia (Rubiaceae), Mimosa pudica L. and Acacia pennata L. calabura is an exotic fruit tree and cannot be Willd (Mimoceae), Rungia repens Nees (Acantheceae), recommended for growing within cashew plantations as it Leucas aspera Willd. (Labiatae) and Muntingia calabura has been recorded as a refugee-host for an important, key L. (Tiliaceae). Whereas, during the flowering period of pest of cashew, Helopeltis spp. (Miridae: Heteroptera) cashew, Blumea lacera L. and B. oxydonta D.C. (Sundararaju et al, 2002). (Asteraceae), Rungia parviflora (Retz.) Nees and ACKNOWLEDGEMENT Muntingia calabura were observed as additional floral The author thanks the Director, Directorate of resources. In coastal Tamil Nadu, Ocimum americanum Cashew Research, Puttur for providing facilities. He also L. and O. adscendens Willd. (Labiatae), Cleome viscosa thanks Shri Laxmipathi for technical assistance and L. (Capparidaceae), Oldenlandia umbellata L. Biosystematics Unit of Department of Entomology, GKVK, (Rubiaceae) and L. aspera were found to be floral resources University of Agricultural Sciences, Bangalore for during the lean period. Cleome viscosa, O. adscendens, identification of Ceratina (Pithitis) binghami. Identification and, L. aspera and Celosia sp. (Amaranthaceae) were of various flora of pollinators by Botanical Survey of India, observed as additional flower resources during the flowering Southern Regional Centre, Coimbatore, is gratefully period. acknowledged.

54 J. Hortl. Sci. Vol. 6(1):52-55, 2011 Diversity of bee pollinators and flora in cashew

REFERENCES Reddi, E.U.B. 1993. Pollination studies of cashew in India : an overview. In: ( Eds.Veeresh , G.K., Umashaankar, Ambethgar, V. 2002. visitors of cashew inflorescence R. and Ganeshaiah, K.N.). Proc. Int’l. Symp. Polln. in north-eastern zone of Tamil Nadu, India. Progr. Trop. UAS, Bangalore, pp. 321-324 Hort., 34:223-229 Reddi, E.U.B. 1995. Insect pollination in cashew. In: ( Ed. Abrol, D.P. 1997. Bees and Bee Keeping in India. Kalyani Sihag, R.C.). Pollination Biology: Environmental Publishers, Delhi, pp. 303-308 Factors & Pollination. Rajendra Scientific Batra, S.W.T. 1977. Bees of India (Apidea), their behaviour, management and a key to the genera. Orient. Publishers, Hisar. pp. 68-74 Insects, 11:289-324 Sundararaju, D. 2000. Foraging behaviour of pollinators on Batra, S.W.T.1994. Diversify with pollen bees. Am. Bee J., cashew. The Cashew, 14:17-20 134:591-593. Sundararaju, D. 2003. Occurrence of bee fauna and extent Bhattacharya, A. 2004. Flower visitors and fruit set of of pollination in insecticide sprayed ecosystem of Anacardium occidentale. Ann. Bot. Fennici., cashew. J. Palynol., 39:121-125 41:385-392 Sundararaju, D. 2004. Evaluation of promising new Devasahayam, S. 1986. Some observation on insects visiting insecticides in large plots for management of tea cashew inflorescence. Cashew Bull., 23:1-5 mosquito bug on cashew. J. Plantn. Crops, Free, B.J. 1993. Insect Pollination of Crops. Academic Press, 32(Suppl.):285- 288 London, pp 122-124 Sundararaju, D. 2011. Studies on extent of pollination and Frietas, B.M. 1997. Changes with time in the germinability fruitset in cashew. J. Plantn. Crops, 39 (in press) of cashew (Anacardium occidentale) pollen grains Sundararaju, D., Raviprasad, T.N. and Bhat, P.S. 2002. New found on different body areas of its pollinator bees. refuge host plant for Helopeltis spp. Insect Envir., Rev. Brasil Biol., 57:289-294 8:137-138 Frietas, B.M. and Paxton, R.J.1996. The role of wind and Thimmaraju, K.R. and Lakshmi Raju. 1993. Pollinator limited insects in cashew (Anacardium occidentale) fruit-set in cashew. In: (Eds. Veeresh , G.K., pollination in NE Brazil. J. Agril. Sci.,126:319-326 Umashaankar, R. and Ganeshaiah, K.N.). Proc. Int’l. Ohler, J.G. 1979. Cashew. Koniklijk Institute Voor de Tropen, Symp. Polln. Trop. UAS, Bangalore, pp. 43 Amsterdam, pp260

(MS Received 04 December 2010, Revised 25 April 2011)

55 J. Hortl. Sci. Vol. 6(1):52-55, 2011